Question: If $x \boxdot y = x+7y$ and $x \bigtriangledown y = 3x^{2}+y^{2}$, find $(-3 \bigtriangledown -5) \boxdot -4$.
Explanation: First, find $-3 \bigtriangledown -5$ $ -3 \bigtriangledown -5 = 3(-3)^{2}+(-5)^{2}$ $ \hphantom{-3 \bigtriangledown -5} = 52$ Now, find $52 \boxdot -4$ $ 52 \boxdot -4 = 52+(7)(-4)$ $ \hphantom{52 \boxdot -4} = 24$.